1. Field of the Technology
The technology is related to systems and methods that monitor and analyze network events occurring within a Voice over Internet Protocol (VOIP) system to detect conditions that could result in poor call quality. The technology is also related to methods of automatically taking corrective action to correct detected problems.
2. Background of the Technology
VOIP telephony systems are used to transmit voice communications over a data network using Internet Protocol digital data packets. VOIP telephony systems can supplement and/or replace existing analog telephone systems. In VOIP systems, analog voice signals are converted into digital data packets which traverse the data network, and the data packets are then converted back into voice signals.
In order to conduct a VOIP telephone call, the calling party must have an IP telephony device which is capable of converting analog voice signals into digital data packets and transmitting the data packets over the Internet. The IP telephony device must also be capable of receiving data packets from a third party and converting those data packets into analog voice signals which are played to the user.
IP telephony devices can take many different forms. An IP telephone could resemble a normal analog telephone, but the IP telephone would be capable of sending and receiving a call in the form of digital data packets. An IP telephony device could also be embodied in a computer with a microphone and a speaker, where the computer is running software that enables the computer to conduct IP based telephone calls. An IP telephony device could also be a mobile telephony device capable of communicating via either a cellular telephony network, or via wireless digital data communications. In the following description, reference is made to IP telephony devices. The term “IP telephony device” is intended to cover any physical device and any associated software which enable a user to conduct an IP based telephone call.
It is also possible for a user to interact with a VOIP telephony system using a normal analog telephone. In these instances, an interface device is provided between the data network and the analog telephone. The interface device converts analog telephone signals from the analog telephone into digital data packets that traverse the data network. Also, the interface device converts incoming digital data packets into analog signals that can be used by the analog telephone. Thus, the term “IP telephony device” is also intended to encompass the combination of an analog telephone and an interface device.
IP telephony devices are typically connected to the Internet, or to some other data network, through some type of router device. In one common scenario, a residential customer will have a high speed broadband Internet connection that runs into the customer's house and which terminates at a router. The router, in turn, is connected to a local network within the customer's house. The IP telephony device used to conduct VOIP telephone calls is then connected to the local network, or directly to the router itself. The router is used to provide a high speed Internet connection to not only the IP telephony device, but also to computers, and possibly to an entertainment system such as a cable television set top box. Thus, the IP telephony device must share access to the Internet connection provided by the router.
Typically, only a single IP address is assigned to the router. Because multiple devices within the user's home or office share access to the Internet connection, it is necessary for the router to conduct some sort of network address translation so that all of the devices within the customer's home or office can share the single IP address assigned to the router.
In addition, the router will also typically include some type of firewall software which is used to prevent unauthorized data packets from entering the local network and being delivered to the devices connected to the local network. As will be explained in more detail below, the firewall and the network address translation systems used by the router can make it difficult to establish and maintain a VOIP telephone call to an IP telephony device connected to the router or the local network.
In order to conduct a high quality VOIP telephone call, both the originating IP telephony device and the destination IP telephony device must be able to transmit and receive a certain number of data packets each second. If sufficient communications bandwidth is not available, the call quality will be degraded. Likewise, if data packets sent between the two IP telephony devices are lost in transit, or if the data packets arrive too far out of sequence, the call quality is degraded.
Insufficient bandwidth problems can occur when an IP telephony device is sharing access to a broadband Internet connection with other devices, and those other device consume too much of the available bandwidth. Depending on the circumstances, the other devices on the local network could substantially continuously consume too much of the available bandwidth, or the other devices might only periodically consume too much of the bandwidth.
For instance, if a cable set-top box in a customer's home is streaming a movie to a display screen, the streaming of the movie might continuously consume so much of the available bandwidth that any VOIP calls suffer degraded call quality. On the other hand, if a computer located in the customer's home only periodically downloads large files, the computer would only periodically consume too much of the available bandwidth. As a result, a VOIP call being conducted while the computer conducts a download would only temporarily experience degraded call quality. As soon as the file is fully downloaded to the computer, the call quality would return to normal.